Optical imaging lens

ABSTRACT

An optical imaging lens includes a first lens element, a second lens, a third lens element and a fourth lens element from an object side to an image side in order along an optical axis. An optical axis region of the object-side surface of the first lens element is convex, and an optical axis region of the image-side surface of the third lens element is concave. The lens elements included by the optical imaging lens are only the four lens elements described above. Tavg is an average of four thicknesses from the first lens element to the fourth lens element along the optical axis, an Abbe number of the first lens element is υ1, and an Abbe number of the second lens element is υ2 so that the optical imaging lens satisfies: Tavg≤300 μm, and |υ1−υ2|≤30.000.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to an optical imaging lens.Specifically speaking, the present invention is directed to an opticalimaging lens for using in a portable electronic device such as a mobilephone, a camera, a tablet personal computer, or a personal digitalassistant (PDA) for taking pictures or for recording videos. Since theoptical imaging lens of the present invention has a smaller volume and alarger field of view, it may also be applied to medical equipment suchas an endoscope.

2. Description of the Prior Art

The specifications of consumer electronic products are changing from dayto day, not only it keeps becoming lighter and thinner, but also thespecifications of key components of electronic products such as opticalimaging lens are improving to meet the requirements of consumers. Inaddition to the imaging quality and to the volume of optical imaginglens, it is also important to improve the field of view and the f-numberof an optical imaging lens. Therefore, in the field of an opticalimaging lens design, it is also necessary to have a compromise betweenthe quality of and performance in addition to the pursuit of thinning ofan optical imaging lens.

However, the design of an optical imaging lens is not just to reduce thelens with good imaging quality in equal proportion to yield an opticalimaging lens of compromised imaging quality and miniaturization.Practical problems of aspects of production such as manufacture andassembly yield must also be taken into consideration because the designprocess involves not only the material characteristics, the lens elementthickness or the air gap configuration. Therefore, the technicaldifficulty of miniaturized lens elements is obviously much higher thanthat of traditional lens elements. It has always been the goal of thecontinuous improvement in this field to learn how to make opticalimaging lens meet the requirements of consumer electronic products andto continuously improve the imaging quality.

SUMMARY OF THE INVENTION

In light of the above, the present invention proposes an optical imaginglens of four lens elements which has smaller Fno, a smaller volume, alarger field of view, excellent imaging quality, good opticalperformance and is technically possible. The optical imaging lens offour lens elements of the present invention from an object side to animage side in order along an optical axis has a first lens element, asecond lens element, a third lens element and a fourth lens element.Each lens element of the first lens element, the second lens element,the third lens element and the fourth lens element in the opticalimaging lens of four lens elements of the present invention respectivelyhas an object-side surface which faces toward the object side to allowimaging rays to pass through as well as an image-side surface whichfaces toward the image side to allow the imaging rays to pass through.

In one embodiment of the present invention, an optical axis region ofthe object-side surface of the second lens element is convex, an opticalaxis region of the image-side surface of the third lens element isconcave and lens elements included by the optical imaging lens are onlythe four lens elements described above to satisfy the relationships:Tavg≤350 μm, Gmax/Tmin≥1.000, Tmax−T2≤λ; λ=0 when T2=Tmax, and λ=90 μmif T2≠Tmax.

In another embodiment of the present invention, the first lens elementhas negative refracting power and an optical axis region of theobject-side surface of the first lens element is convex, an optical axisregion of the image-side surface of the third lens element is concaveand lens elements included by the optical imaging lens are only the fourlens elements described above to satisfy the relationships: Tavg≤400 μm,Tmax−T2≤λ, T3−Tmin≤δ; λ=0 when T2=Tmax, λ=90 μm if T2≠Tmax, δ=0 whenT3=Tmin, and δ=150 μm if T3≠Tmin.

In another embodiment of the present invention, an optical axis regionof the object-side surface of the first lens element is convex, anoptical axis region of the image-side surface of the third lens elementis concave and lens elements included by the optical imaging lens areonly the four lens elements described above to satisfy therelationships: Tavg≤300 μm, and |υ1−υ2|≤30.000.

In the optical imaging lens of the present invention, the embodimentsmay also selectively satisfy the following optical relationships:

1. TTL/T2≤8.700; 2. AAG/Tmin≤7.700; 3. EFL/(G23+T3+G34)≥1.490; 4.(ALT+EFL)/(G12+T3+T4)≤3.200; 5. EFL/Gmax≤3.500;

6. HFOV/(TTL+EFL)≥18.000 degrees/mm;

7. TL/(G12+T4)≤2.700; 8. AAG/T1≤3.500; 9. (EFL+BFL)/(T1+T4)≤3.700;

10. υ3+υ4≥70.000;

11. BFL/(G12+G34)≤2.900;

12. HFOV/Fno≥18.500 degrees;

13. TL/(G12+G34)≤5.100; 14. ALT/(T1+G34)≤5.000; 15. BFL/(G23+T4)≥1.500;16. TTL/ImgH≥3.000; 17. (ALT+BFL)/(AAG+EFL)≥0.900; 18.(TTL+EFL)/(Tmax+Tmax2)≤5.850; 19. G12≤ALT;

20. υ1+υ2≥93.000.

In the present invention, T1 is a thickness of the first lens elementalong the optical axis, T2 is a thickness of the second lens elementalong the optical axis, T3 is a thickness of the third lens elementalong the optical axis, T4 is a thickness of the fourth lens elementalong the optical axis, G12 is an air gap between the first lens elementand the second lens element along the optical axis, G23 is an air gapbetween the second lens element and the third lens element along theoptical axis, G34 is an air gap between the third lens element and thefourth lens element along the optical axis. AAG is a sum of three airgaps from the first lens element to the fourth lens element along theoptical axis, i.e. a sum of G12, G23 and G34; ALT is a sum of thethicknesses of four lens elements from the first lens element to thefourth lens element along the optical axis, i.e. a sum of T1, T2, T3 andT4; Tmax is the largest thickness of four lens elements from the firstlens element to the fourth lens element along the optical axis, that is,the largest thickness of T1, T2, T3 and T4; Tmax2 is the second largestthickness of four lens elements from the first lens element to thefourth lens element along the optical axis, that is, the second largestthickness of T1, T2, T3 and T4; Tmin is the smallest thickness of fourlens elements from the first lens element to the fourth lens elementalong the optical axis, that is, the smallest thickness of T1, T2, T3and T4; Tavg is an average of four thicknesses from the first lenselement to the fourth lens element along the optical axis, that is, anaverage of T1, T2, T3 and T4; Gmax is the largest value of three airgaps from the first lens element to the fourth lens element along theoptical axis, that is, the largest air gap of G12, G23 and G34; TL is adistance from the object-side surface of the first lens element to theimage-side surface of the fourth lens element along the optical axis;TTL is a distance from the object-side surface of the first lens elementto an image plane along the optical axis, namely a system length of theoptical imaging lens; BFL is a distance from the image-side surface ofthe fourth lens element to the image plane along the optical axis; EFLis an effective focal length of the optical imaging lens; ImgH is animage height of the optical imaging lens, and Fno is a f-number of theoptical imaging lens.

Besides, an Abbe number of the first lens element is υ1; an Abbe numberof the second lens element is υ2; an Abbe number of the third lenselement is υ3; an Abbe number of the fourth lens element is υ4.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrate the methods for determining the surface shapes andfor determining optical axis region or periphery region of one lenselement.

FIG. 6 illustrates a first embodiment of the optical imaging lens of thepresent invention.

FIG. 7A illustrates the longitudinal spherical aberration on the imageplane of the first embodiment.

FIG. 7B illustrates the field curvature aberration on the sagittaldirection of the first embodiment.

FIG. 7C illustrates the field curvature aberration on the tangentialdirection of the first embodiment.

FIG. 7D illustrates the distortion aberration of the first embodiment.

FIG. 8 illustrates a second embodiment of the optical imaging lens ofthe present invention.

FIG. 9A illustrates the longitudinal spherical aberration on the imageplane of the second embodiment.

FIG. 9B illustrates the field curvature aberration on the sagittaldirection of the second embodiment.

FIG. 9C illustrates the field curvature aberration on the tangentialdirection of the second embodiment.

FIG. 9D illustrates the distortion aberration of the second embodiment.

FIG. 10 illustrates a third embodiment of the optical imaging lens ofthe present invention.

FIG. 11A illustrates the longitudinal spherical aberration on the imageplane of the third embodiment.

FIG. 11B illustrates the field curvature aberration on the sagittaldirection of the third embodiment.

FIG. 11C illustrates the field curvature aberration on the tangentialdirection of the third embodiment.

FIG. 11D illustrates the distortion aberration of the third embodiment.

FIG. 12 illustrates a fourth embodiment of the optical imaging lens ofthe present invention.

FIG. 13A illustrates the longitudinal spherical aberration on the imageplane of the fourth embodiment.

FIG. 13B illustrates the field curvature aberration on the sagittaldirection of the fourth embodiment.

FIG. 13C illustrates the field curvature aberration on the tangentialdirection of the fourth embodiment.

FIG. 13D illustrates the distortion aberration of the fourth embodiment.

FIG. 14 illustrates a fifth embodiment of the optical imaging lens ofthe present invention.

FIG. 15A illustrates the longitudinal spherical aberration on the imageplane of the fifth embodiment.

FIG. 15B illustrates the field curvature aberration on the sagittaldirection of the fifth embodiment.

FIG. 15C illustrates the field curvature aberration on the tangentialdirection of the fifth embodiment.

FIG. 15D illustrates the distortion aberration of the fifth embodiment.

FIG. 16 illustrates a sixth embodiment of the optical imaging lens ofthe present invention.

FIG. 17A illustrates the longitudinal spherical aberration on the imageplane of the sixth embodiment.

FIG. 17B illustrates the field curvature aberration on the sagittaldirection of the sixth embodiment.

FIG. 17C illustrates the field curvature aberration on the tangentialdirection of the sixth embodiment.

FIG. 17D illustrates the distortion aberration of the sixth embodiment.

FIG. 18 illustrates a seventh embodiment of the optical imaging lens ofthe present invention.

FIG. 19A illustrates the longitudinal spherical aberration on the imageplane of the seventh embodiment.

FIG. 19B illustrates the field curvature aberration on the sagittaldirection of the seventh embodiment.

FIG. 19C illustrates the field curvature aberration on the tangentialdirection of the seventh embodiment.

FIG. 19D illustrates the distortion aberration of the seventhembodiment.

FIG. 20 illustrates an eighth embodiment of the optical imaging lens ofthe present invention.

FIG. 21A illustrates the longitudinal spherical aberration on the imageplane of the eighth embodiment.

FIG. 21B illustrates the field curvature aberration on the sagittaldirection of the eighth embodiment.

FIG. 21C illustrates the field curvature aberration on the tangentialdirection of the eighth embodiment.

FIG. 21D illustrates the distortion aberration of the eighth embodiment.

FIG. 22 illustrates a ninth embodiment of the optical imaging lens ofthe present invention.

FIG. 23A illustrates the longitudinal spherical aberration on the imageplane of the ninth embodiment.

FIG. 23B illustrates the field curvature aberration on the sagittaldirection of the ninth embodiment.

FIG. 23C illustrates the field curvature aberration on the tangentialdirection of the ninth embodiment.

FIG. 23D illustrates the distortion aberration of the ninth embodiment.

FIG. 24 illustrates a tenth embodiment of the optical imaging lens ofthe present invention.

FIG. 25A illustrates the longitudinal spherical aberration on the imageplane of the tenth embodiment.

FIG. 25B illustrates the field curvature aberration on the sagittaldirection of the tenth embodiment.

FIG. 25C illustrates the field curvature aberration on the tangentialdirection of the tenth embodiment.

FIG. 25D illustrates the distortion aberration of the tenth embodiment.

FIG. 26 illustrates an eleventh embodiment of the optical imaging lensof the present invention.

FIG. 27A illustrates the longitudinal spherical aberration on the imageplane of the eleventh embodiment.

FIG. 27B illustrates the field curvature aberration on the sagittaldirection of the eleventh embodiment.

FIG. 27C illustrates the field curvature aberration on the tangentialdirection of the eleventh embodiment.

FIG. 27D illustrates the distortion aberration of the eleventhembodiment.

FIG. 28 illustrates a twelfth embodiment of the optical imaging lens ofthe present invention.

FIG. 29A illustrates the longitudinal spherical aberration on the imageplane of the twelfth embodiment.

FIG. 29B illustrates the field curvature aberration on the sagittaldirection of the twelfth embodiment.

FIG. 29C illustrates the field curvature aberration on the tangentialdirection of the twelfth embodiment.

FIG. 29D illustrates the distortion aberration of the twelfthembodiment.

FIG. 30 illustrates a thirteenth embodiment of the optical imaging lensof the present invention.

FIG. 31A illustrates the longitudinal spherical aberration on the imageplane of the thirteenth embodiment.

FIG. 31B illustrates the field curvature aberration on the sagittaldirection of the thirteenth embodiment.

FIG. 31C illustrates the field curvature aberration on the tangentialdirection of the thirteenth embodiment.

FIG. 31D illustrates the distortion aberration of the thirteenthembodiment.

FIG. 32 shows the optical data of the first embodiment of the opticalimaging lens.

FIG. 33 shows the aspheric surface data of the first embodiment.

FIG. 34 shows the optical data of the second embodiment of the opticalimaging lens.

FIG. 35 shows the aspheric surface data of the second embodiment.

FIG. 36 shows the optical data of the third embodiment of the opticalimaging lens.

FIG. 37 shows the aspheric surface data of the third embodiment.

FIG. 38 shows the optical data of the fourth embodiment of the opticalimaging lens.

FIG. 39 shows the aspheric surface data of the fourth embodiment.

FIG. 40 shows the optical data of the fifth embodiment of the opticalimaging lens.

FIG. 41 shows the aspheric surface data of the fifth embodiment.

FIG. 42 shows the optical data of the sixth embodiment of the opticalimaging lens.

FIG. 43 shows the aspheric surface data of the sixth embodiment.

FIG. 44 shows the optical data of the seventh embodiment of the opticalimaging lens.

FIG. 45 shows the aspheric surface data of the seventh embodiment.

FIG. 46 shows the optical data of the eighth embodiment of the opticalimaging lens.

FIG. 47 shows the aspheric surface data of the eighth embodiment.

FIG. 48 shows the optical data of the ninth embodiment of the opticalimaging lens.

FIG. 49 shows the aspheric surface data of the ninth embodiment.

FIG. 50 shows the optical data of the tenth embodiment of the opticalimaging lens.

FIG. 51 shows the aspheric surface data of the tenth embodiment.

FIG. 52 shows the optical data of the eleventh embodiment of the opticalimaging lens.

FIG. 53 shows the aspheric surface data of the eleventh embodiment.

FIG. 54 shows the optical data of the twelfth embodiment of the opticalimaging lens.

FIG. 55 shows the aspheric surface data of the twelfth embodiment.

FIG. 56 shows the optical data of the thirteenth embodiment of theoptical imaging lens.

FIG. 57 shows the aspheric surface data of the thirteenth embodiment.

FIG. 58 and FIG. 59 show some important parameters and ratios in theembodiments.

DETAILED DESCRIPTION

The terms “optical axis region”, “periphery region”, “concave”, and“convex” used in this specification and claims should be interpretedbased on the definition listed in the specification by the principle oflexicographer.

In the present disclosure, the optical system may comprise at least onelens element to receive imaging rays that are incident on the opticalsystem over a set of angles ranging from parallel to an optical axis toa half field of view (HFOV) angle with respect to the optical axis. Theimaging rays pass through the optical system to produce an image on animage plane. The term “a lens element having positive refracting power(or negative refracting power)” means that the paraxial refracting powerof the lens element in Gaussian optics is positive (or negative). Theterm “an object-side (or image-side) surface of a lens element” refersto a specific region of that surface of the lens element at whichimaging rays can pass through that specific region. Imaging rays includeat least two types of rays: a chief ray Lc and a marginal ray Lm (asshown in FIG. 1). An object-side (or image-side) surface of a lenselement can be characterized as having several regions, including anoptical axis region, a periphery region, and, in some cases, one or moreintermediate regions, as discussed more fully below.

FIG. 1 is a radial cross-sectional view of a lens element 100. Tworeferential points for the surfaces of the lens element 100 can bedefined: a central point, and a transition point. The central point of asurface of a lens element is a point of intersection of that surface andthe optical axis I. As illustrated in FIG. 1, a first central point CP1may be present on the object-side surface 110 of lens element 100 and asecond central point CP2 may be present on the image-side surface 120 ofthe lens element 100. The transition point is a point on a surface of alens element, at which the line tangent to that point is perpendicularto the optical axis I. The optical boundary OB of a surface of the lenselement is defined as a point at which the radially outermost marginalray Lm passing through the surface of the lens element intersects thesurface of the lens element. All transition points lie between theoptical axis I and the optical boundary OB of the surface of the lenselement. A surface of the lens element 100 may have no transition pointor have at least one transition point. If multiple transition points arepresent on a single surface, then these transition points aresequentially named along the radial direction of the surface withreference numerals starting from the first transition point. Forexample, the first transition point, e.g., TP1, (closest to the opticalaxis I), the second transition point, e.g., TP2, (as shown in FIG. 4),and the Nth transition point (farthest from the optical axis I).

When a surface of the lens element has at least one transition point,the region of the surface of the lens element from the central point tothe first transition point TP1 is defined as the optical axis region,which includes the central point. The region located radially outside ofthe farthest transition point (the Nth transition point) from theoptical axis I to the optical boundary OB of the surface of the lenselement is defined as the periphery region. In some embodiments, theremay be intermediate regions present between the optical axis region andthe periphery region, with the number of intermediate regions dependingon the number of the transition points. When a surface of the lenselement has no transition point, the optical axis region is defined as aregion of 0%-50% of the distance between the optical axis I and theoptical boundary OB of the surface of the lens element, and theperiphery region is defined as a region of 50%-100% of the distancebetween the optical axis I and the optical boundary OB of the surface ofthe lens element.

The shape of a region is convex if a collimated ray being parallel tothe optical axis I and passing through the region is bent toward theoptical axis I such that the ray intersects the optical axis I on theimage side A2 of the lens element. The shape of a region is concave ifthe extension line of a collimated ray being parallel to the opticalaxis I and passing through the region intersects the optical axis I onthe object side A1 of the lens element.

Additionally, referring to FIG. 1, the lens element 100 may also have amounting portion 130 extending radially outward from the opticalboundary OB. The mounting portion 130 is typically used to physicallysecure the lens element to a corresponding element of the optical system(not shown). Imaging rays do not reach the mounting portion 130. Thestructure and shape of the mounting portion 130 are only examples toexplain the technologies, and should not be taken as limiting the scopeof the present disclosure. The mounting portion 130 of the lens elementsdiscussed below may be partially or completely omitted in the followingdrawings.

Referring to FIG. 2, optical axis region Z1 is defined between centralpoint CP and first transition point TP1. Periphery region Z2 is definedbetween TP1 and the optical boundary OB of the surface of the lenselement. Collimated ray 211 intersects the optical axis I on the imageside A2 of lens element 200 after passing through optical axis regionZ1, i.e., the focal point of collimated ray 211 after passing throughoptical axis region Z1 is on the image side A2 of the lens element 200at point R in FIG. 2. Accordingly, since the ray itself intersects theoptical axis I on the image side A2 of the lens element 200, opticalaxis region Z1 is convex. On the contrary, collimated ray 212 divergesafter passing through periphery region Z2. The extension line EL ofcollimated ray 212 after passing through periphery region Z2 intersectsthe optical axis I on the object side A1 of lens element 200, i.e., thefocal point of collimated ray 212 after passing through periphery regionZ2 is on the object side A1 at point M in FIG. 2. Accordingly, since theextension line EL of the ray intersects the optical axis I on the objectside A1 of the lens element 200, periphery region Z2 is concave. In thelens element 200 illustrated in FIG. 2, the first transition point TP1is the border of the optical axis region and the periphery region, i.e.,TP1 is the point at which the shape changes from convex to concave.

Alternatively, there is another way for a person having ordinary skillin the art to determine whether an optical axis region is convex orconcave by referring to the sign of “Radius of curvature” (the “R”value), which is the paraxial radius of shape of a lens surface in theoptical axis region. The R value is commonly used in conventionaloptical design software such as Zemax and CodeV. The R value usuallyappears in the lens data sheet in the software. For an object-sidesurface, a positive R value defines that the optical axis region of theobject-side surface is convex, and a negative R value defines that theoptical axis region of the object-side surface is concave. Conversely,for an image-side surface, a positive R value defines that the opticalaxis region of the image-side surface is concave, and a negative R valuedefines that the optical axis region of the image-side surface isconvex. The result found by using this method should be consistent withthe method utilizing intersection of the optical axis by rays/extensionlines mentioned above, which determines surface shape by referring towhether the focal point of a collimated ray being parallel to theoptical axis I is on the object-side or the image-side of a lenselement. As used herein, the terms “a shape of a region is convex(concave),” “a region is convex (concave),” and “a convex- (concave-)region,” can be used alternatively.

FIG. 3, FIG. 4 and FIG. 5 illustrate examples of determining the shapeof lens element regions and the boundaries of regions under variouscircumstances, including the optical axis region, the periphery region,and intermediate regions as set forth in the present specification.

FIG. 3 is a radial cross-sectional view of a lens element 300. Asillustrated in FIG. 3, only one transition point TP1 appears within theoptical boundary OB of the image-side surface 320 of the lens element300. Optical axis region Z1 and periphery region Z2 of the image-sidesurface 320 of lens element 300 are illustrated. The R value of theimage-side surface 320 is positive (i.e., R>0). Accordingly, the opticalaxis region Z1 is concave.

In general, the shape of each region demarcated by the transition pointwill have an opposite shape to the shape of the adjacent region(s).Accordingly, the transition point will define a transition in shape,changing from concave to convex at the transition point or changing fromconvex to concave. In FIG. 3, since the shape of the optical axis regionZ1 is concave, the shape of the periphery region Z2 will be convex asthe shape changes at the transition point TP1.

FIG. 4 is a radial cross-sectional view of a lens element 400. Referringto FIG. 4, a first transition point TP1 and a second transition pointTP2 are present on the object-side surface 410 of lens element 400. Theoptical axis region Z1 of the object-side surface 410 is defined betweenthe optical axis I and the first transition point TP1. The R value ofthe object-side surface 410 is positive (i.e., R>0). Accordingly, theoptical axis region Z1 is convex.

The periphery region Z2 of the object-side surface 410, which is alsoconvex, is defined between the second transition point TP2 and theoptical boundary OB of the object-side surface 410 of the lens element400. Further, intermediate region Z3 of the object-side surface 410,which is concave, is defined between the first transition point TP1 andthe second transition point TP2. Referring once again to FIG. 4, theobject-side surface 410 includes an optical axis region Z1 locatedbetween the optical axis I and the first transition point TP1, anintermediate region Z3 located between the first transition point TP1and the second transition point TP2, and a periphery region Z2 locatedbetween the second transition point TP2 and the optical boundary OB ofthe object-side surface 410. Since the shape of the optical axis regionZ1 is designed to be convex, the shape of the intermediate region Z3 isconcave as the shape of the intermediate region Z3 changes at the firsttransition point TP1, and the shape of the periphery region Z2 is convexas the shape of the periphery region Z2 changes at the second transitionpoint TP2.

FIG. 5 is a radial cross-sectional view of a lens element 500. Lenselement 500 has no transition point on the object-side surface 510 ofthe lens element 500. For a surface of a lens element with no transitionpoint, for example, the object-side surface 510 the lens element 500,the optical axis region Z1 is defined as the region of 0%-50% of thedistance between the optical axis I and the optical boundary OB of thesurface of the lens element and the periphery region is defined as theregion of 50%-100% of the distance between the optical axis I and theoptical boundary OB of the surface of the lens element. Referring tolens element 500 illustrated in FIG. 5, the optical axis region Z1 ofthe object-side surface 510 is defined between the optical axis I and50% of the distance between the optical axis I and the optical boundaryOB. The R value of the object-side surface 510 is positive (i.e., R>0).Accordingly, the optical axis region Z1 is convex. For the object-sidesurface 510 of the lens element 500, because there is no transitionpoint, the periphery region Z2 of the object-side surface 510 is alsoconvex. It should be noted that lens element 500 may have a mountingportion (not shown) extending radially outward from the periphery regionZ2.

As shown in FIG. 6, the optical imaging lens 1 of four lens elements ofthe present invention, sequentially located from an object side A1(where an object is located) to an image side A2 along an optical axisI, has a first lens element 10, an aperture stop (ape. stop) 80, asecond lens element 20, a third lens element 30, a fourth lens element40 and an image plane 91. Generally speaking, the first lens element 10,the second lens element 20, the third lens element 30 and the fourthlens element 40 may be made of a transparent plastic material but thepresent invention is not limited to this. Each has an appropriaterefracting power. In the optical imaging lens 1 of the presentinvention, lens elements having refracting power included by the opticalimaging lens 1 are only the first lens element 10, the second lenselement 20, the third lens element 30 and the fourth lens element 40,the four lens elements, described above. The optical axis I is theoptical axis of the entire optical imaging lens 1, and the optical axisof each of the lens elements coincides with the optical axis of theoptical imaging lens 1.

Furthermore, the optical imaging lens 1 includes an aperture stop (ape.stop) 80 disposed in an appropriate position. In FIG. 6, the aperturestop 80 is disposed between the first lens element 10 and the secondlens element 20. When light emitted or reflected by an object (notshown) which is located at the object side A1 enters the optical imaginglens 1 of the present invention, it forms a clear and sharp image on theimage plane 91 at the image side A2 after passing through the first lenselement 10, the aperture stop 80, the second lens element 20, the thirdlens element 30, the fourth lens element 40 and the filter 90. Inembodiments of the present invention, the filter 90 may be a filter ofvarious suitable functions, for example, the filter 90 may be aninfrared cut-off filter (IR cut filter), placed between the fourth lenselement 40 and the image plane 91, to keep the infrared light in theimaging rays from reaching the image plane 91 to jeopardize the imagingquality.

Each lens element in the optical imaging lens 1 of the present inventionhas an object-side surface facing toward the object side A1 and allowingimaging rays to pass through as well as an image-side surface facingtoward the image side A2 and allowing the imaging rays to pass through.For example, the first lens element 10 has an object-side surface 11 andan image-side surface 12; the second lens element 20 has an object-sidesurface 21 and an image-side surface 22; the third lens element 30 hasan object-side surface 31 and an image-side surface 32; the fourth lenselement 40 has an object-side surface 41 and an image-side surface 42.In addition, each object-side surface and image-side surface in theoptical imaging lens 1 of the present invention has an optical axisregion and a periphery region.

Each lens element in the optical imaging lens 1 of the present inventionfurther has a thickness T along the optical axis I. For example, thefirst lens element 10 has a first lens element thickness T1, the secondlens element 20 has a second lens element thickness T2, the third lenselement 30 has a third lens element thickness T3, the fourth lenselement 40 has a fourth lens element thickness T4. Therefore, the sum ofthe thicknesses of four lens elements from the first lens element 10 tothe fourth lens element 40 in the optical imaging lens 1 along theoptical axis I is ALT. That is, ALT=T1+T2+T3+T4.

In addition, between two adjacent lens elements in the optical imaginglens 1 of the present invention there may be an air gap along theoptical axis I. For example, there is an air gap G12 between the firstlens element 10 and the second lens element 20, an air gap G23 betweenthe second lens element 20 and the third lens element 30, and an air gapG34 between the third lens element 30 and the fourth lens element 40.Therefore, the sum of three air gaps from the first lens element 10 tothe fourth lens element 40 along the optical axis I is AAG. That is,AAG=G12+G23+G34.

In addition, a distance from the object-side surface 11 of the firstlens element 10 to the image plane 91 along the optical axis I is TTL,namely a system length of the optical imaging lens 1; an effective focallength of the optical imaging lens 1 is EFL; a distance from theobject-side surface 11 of the first lens element 10 to the image-sidesurface 42 of the fourth lens element 40 along the optical axis I is TL;HFOV stands for the half field of view which is half of the field ofview of the entire optical imaging lens 1; ImgH is an image height ofthe optical imaging lens 1, and Fno is a f-number of the optical imaginglens 1.

When the filter 90 is placed between the fourth lens element 40 and theimage plane 91, an air gap between the fourth lens element 40 and thefilter 90 along the optical axis I is G4F; a thickness of the filter 90along the optical axis I is TF; an air gap between the filter 90 and theimage plane 91 along the optical axis I is GFP; and a distance from theimage-side surface 42 of the fourth lens element 40 to the image plane91 along the optical axis I is a back focal length, BFL. Therefore,BFL=G4F+TF+GFP.

Furthermore, a focal length of the first lens element 10 is f1; a focallength of the second lens element 20 is f2; a focal length of the thirdlens element 30 is f3; a focal length of the fourth lens element 40 isf4; a refractive index of the first lens element 10 is n1; a refractiveindex of the second lens element 20 is n2; a refractive index of thethird lens element 30 is n3; a refractive index of the fourth lenselement 40 is n4; an Abbe number of the first lens element 10 is υ1; anAbbe number of the second lens element 20 is υ2; an Abbe number of thethird lens element 30 is υ3; and an Abbe number of the fourth lenselement 40 is υ4.

In the present invention, it is further defined: Tmax is the largestthickness of four lens elements from the first lens element 10 to thefourth lens element 40 along the optical axis I, that is, the largestthickness of T1, T2, T3 and T4; Tmax2 is the second largest thickness offour lens elements from the first lens element 10 to the fourth lenselement 40 along the optical axis I, that is, the second largestthickness of T1, T2, T3 and T4; Tmin is the smallest thickness of fourlens elements from the first lens element 10 to the fourth lens element40 along the optical axis I, that is, the smallest thickness of T1, T2,T3 and T4; Tavg is an average of four thicknesses from the first lenselement 10 to the fourth lens element 40 along the optical axis I, thatis, an average of T1, T2, T3 and T4; Gmax is the largest value of threeair gaps from the first lens element 10 to the fourth lens element 40along the optical axis I, that is, the largest air gap of G12, G23 andG34.

First Embodiment

Please refer to FIG. 6 which illustrates the first embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG. 7Afor the longitudinal spherical aberration on the image plane 91 of thefirst embodiment; please refer to FIG. 7B for the field curvatureaberration on the sagittal direction; please refer to FIG. 7C for thefield curvature aberration on the tangential direction; and please referto FIG. 7D for the distortion aberration. The Y axis of the sphericalaberration in each embodiment is “field of view” for 1.0. The Y axis ofthe field curvature aberration and the distortion in each embodimentstands for “image height” (ImgH), and the image height in the firstembodiment is 0.144 mm.

Lens elements in the optical imaging lens 1 of the first embodiment areonly the four lens elements 10, 20, 30 and 40 with refracting power. Theoptical imaging lens 1 also has an aperture stop 80 and an image plane91. The aperture stop 80 is provided between the first lens element 10and the second lens element 20.

The first lens element 10 has negative refracting power. An optical axisregion 13 of the object-side surface 11 of the first lens element 10 isconvex, and a periphery region 14 of the object-side surface 11 of thefirst lens element 10 is concave. An optical axis region 16 of theimage-side surface 12 of the first lens element 10 is concave, and aperiphery region 17 of the image-side surface 12 of the first lenselement 10 is concave. Besides, both the object-side surface 11 and theimage-side surface 12 of the first lens element 10 are asphericsurfaces, but it is not limited thereto.

The second lens element 20 has positive refracting power. An opticalaxis region 23 of the object-side surface 21 of the second lens element20 is convex, and a periphery region 24 of the object-side surface 21 ofthe second lens element 20 is convex. An optical axis region 26 of theimage-side surface 22 of the second lens element 20 is convex, and aperiphery region 27 of the image-side surface 22 of the second lenselement 20 is convex. Besides, both the object-side surface 21 and theimage-side surface 22 of the second lens element 20 are asphericsurfaces, but it is not limited thereto.

The third lens element 30 has negative refracting power. An optical axisregion 33 of the object-side surface 31 of the third lens element 30 isconcave, and a periphery region 34 of the object-side surface 31 of thethird lens element 30 is concave. An optical axis region 36 of theimage-side surface 32 of the third lens element 30 is concave, and aperiphery region 37 of the image-side surface 32 of the third lenselement 30 is concave. Besides, both the object-side surface 31 and theimage-side surface 32 of the third lens element 30 are asphericsurfaces, but it is not limited thereto.

The fourth lens element 40 has positive refracting power. An opticalaxis region 43 of the object-side surface 41 of the fourth lens element40 is convex, and a periphery region 44 of the object-side surface 41 ofthe fourth lens element 40 is convex. An optical axis region 46 of theimage-side surface 42 of the fourth lens element 40 is convex, and aperiphery region 47 of the image-side surface 42 of the fourth lenselement 40 is convex. Besides, both the object-side surface 41 and theimage-side surface 42 of the fourth lens element 40 are asphericsurfaces, but it is not limited thereto.

In the first lens element 10, the second lens element 20, the third lenselement 30 and the fourth lens element 40 of the optical imaging lens 1of the present invention, there are 8 surfaces, such as the object-sidesurfaces 11/21/31/41 and the image-side surfaces 12/22/32/42. If asurface is aspheric, these aspheric coefficients are defined accordingto the following formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}{a_{i} \times Y^{i}}}}$

In which:

Y represents a perpendicular distance from a point on the asphericsurface to the optical axis;Z represents the depth of an aspheric surface (the perpendiculardistance between the point of the aspheric surface at a distance Y fromthe optical axis and the tangent plane of the vertex of the asphericsurface on the optical axis);R represents the radius of curvature of the lens element surface;K is a conic constant; anda_(i) is the aspheric coefficient of the i^(th) order.

The optical data of the first embodiment of the optical imaging lens 1are shown in FIG. 32 while the aspheric surface data are shown in FIG.33. In the present embodiment and in the following embodiments of theoptical imaging lens, the second-order aspheric coefficients α₂ are all0. In the following embodiments of the optical imaging lens, thef-number of the entire optical imaging lens is Fno, EFL is the effectivefocal length, HFOV stands for the half field of view which is half ofthe field of view of the entire optical imaging lens, and the unit forthe radius of curvature, for the thickness and for the focal length isin millimeters (mm). In this embodiment, EFL=0.207 mm; HFOV=54.721degrees; TTL=1.168 mm; Fno=2.000; ImgH=0.144 mm.

Second Embodiment

Please refer to FIG. 8 which illustrates the second embodiment of theoptical imaging lens 1 of the present invention. It is noted that fromthe second embodiment to the following embodiments, in order to simplifythe figures, only the components different from what the firstembodiment has, and the basic lens elements will be labeled in figures.Other components that are the same as what the first embodiment has,such as the object-side surface, the image-side surface, the opticalaxis region and the periphery region will be omitted in the followingembodiments. Please refer to FIG. 9A for the longitudinal sphericalaberration on the image plane 91 of the second embodiment, please referto FIG. 9B for the field curvature aberration on the sagittal direction,please refer to FIG. 9C for the field curvature aberration on thetangential direction, and please refer to FIG. 9D for the distortionaberration. The components in this embodiment are similar to those inthe first embodiment, but the optical data such as the radius ofcurvature, the lens thickness, the aspheric surface or the back focallength in this embodiment are different from the optical data in thefirst embodiment. In addition, in this embodiment, the optical axisregion 43 of the object-side surface 41 of the fourth lens element 40 isconcave.

The optical data of the second embodiment of the optical imaging lensare shown in FIG. 34 while the aspheric surface data are shown in FIG.35. In this embodiment, EFL=0.327 mm; HFOV=70.074 degrees; TTL=1.657 mm;Fno=2.175; ImgH=0.292 mm. In particular: 1. the field curvatureaberration on the sagittal direction in this embodiment is better thanthe field curvature aberration on the sagittal direction in the firstembodiment; 2. the field curvature aberration on the tangentialdirection in this embodiment is better than the field curvatureaberration on the tangential direction in the first embodiment.

Third Embodiment

Please refer to FIG. 10 which illustrates the third embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.11A for the longitudinal spherical aberration on the image plane 91 ofthe third embodiment; please refer to FIG. 11B for the field curvatureaberration on the sagittal direction; please refer to FIG. 11C for thefield curvature aberration on the tangential direction; and please referto FIG. 11D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the periphery region 14 of the object-side surface 11 of thefirst lens element 10 is convex, the optical axis region 33 of theobject-side surface 31 of the third lens element 30 is convex and theperiphery region 44 of the object-side surface 41 of the fourth lenselement 40 is concave.

The optical data of the third embodiment of the optical imaging lens areshown in FIG. 36 while the aspheric surface data are shown in FIG. 37.In this embodiment, EFL=0.345 mm; HFOV=55.000 degrees; TTL=1.342 mm;Fno=2.000; ImgH=0.311 mm. In particular: the distortion aberration ofthe optical imaging lens in this embodiment is better than that of theoptical imaging lens in the first embodiment.

Fourth Embodiment

Please refer to FIG. 12 which illustrates the fourth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.13A for the longitudinal spherical aberration on the image plane 91 ofthe fourth embodiment; please refer to FIG. 13B for the field curvatureaberration on the sagittal direction; please refer to FIG. 13C for thefield curvature aberration on the tangential direction; and please referto FIG. 13D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the optical axis region 43 of the object-side surface 41 ofthe fourth lens element 40 is concave and the periphery region 44 of theobject-side surface 41 of the fourth lens element 40 is concave.

The optical data of the fourth embodiment of the optical imaging lensare shown in FIG. 38 while the aspheric surface data are shown in FIG.39. In this embodiment, EFL=0.388 mm; HFOV=70.192 degrees; TTL=1.463 mm;Fno=2.291; ImgH=0.336 mm. In particular: 1. the longitudinal sphericalaberration in this embodiment is better than the longitudinal sphericalaberration in the first embodiment.

Fifth Embodiment

Please refer to FIG. 14 which illustrates the fifth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.15A for the longitudinal spherical aberration on the image plane 91 ofthe fifth embodiment; please refer to FIG. 15B for the field curvatureaberration on the sagittal direction; please refer to FIG. 15C for thefield curvature aberration on the tangential direction, and please referto FIG. 15D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the periphery region 37 of the image-side surface 32 of thethird lens element 30 is convex and the optical axis region 43 of theobject-side surface 41 of the fourth lens element 40 is concave.

The optical data of the fifth embodiment of the optical imaging lens areshown in FIG. 40 while the aspheric surface data are shown in FIG. 41.In this embodiment, EFL=0.880 mm; HFOV=59.863 degrees; TTL=1.666 mm;Fno=3.205; ImgH=0.432 mm.

Sixth Embodiment

Please refer to FIG. 16 which illustrates the sixth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.17A for the longitudinal spherical aberration on the image plane 91 ofthe sixth embodiment; please refer to FIG. 17B for the field curvatureaberration on the sagittal direction; please refer to FIG. 17C for thefield curvature aberration on the tangential direction, and please referto FIG. 17D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the periphery region 14 of the object-side surface 11 of thefirst lens element 10 is convex and the optical axis region 33 of theobject-side surface 31 of the third lens element 30 is convex.

The optical data of the sixth embodiment of the optical imaging lens areshown in FIG. 42 while the aspheric surface data are shown in FIG. 43.In this embodiment, EFL=0.635 mm; HFOV=65.010 degrees; TTL=2.977 mm;Fno=2.200; ImgH=0.700 mm. In particular: the distortion aberration ofthe optical imaging lens in this embodiment is better than that of theoptical imaging lens in the first embodiment.

Seventh Embodiment

Please refer to FIG. 18 which illustrates the seventh embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.19A for the longitudinal spherical aberration on the image plane 91 ofthe seventh embodiment; please refer to FIG. 19B for the field curvatureaberration on the sagittal direction; please refer to FIG. 19C for thefield curvature aberration on the tangential direction, and please referto FIG. 19D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the optical axis region 33 of the object-side surface 31 ofthe third lens element 30 is convex.

The optical data of the seventh embodiment of the optical imaging lensare shown in FIG. 44 while the aspheric surface data are shown in FIG.45. In this embodiment, EFL=0.406 mm; HFOV=55.011 degrees; TTL=2.387 mm;Fno=2.050; ImgH=0.350 mm. In particular: the distortion aberration ofthe optical imaging lens in this embodiment is better than that of theoptical imaging lens in the first embodiment.

Eighth Embodiment

Please refer to FIG. 20 which illustrates the eighth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.21A for the longitudinal spherical aberration on the image plane 91 ofthe eighth embodiment; please refer to FIG. 21B for the field curvatureaberration on the sagittal direction; please refer to FIG. 21C for thefield curvature aberration on the tangential direction, and please referto FIG. 21D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the optical axis region 33 of the object-side surface 31 ofthe third lens element 30 is convex.

The optical data of the eighth embodiment of the optical imaging lensare shown in FIG. 46 while the aspheric surface data are shown in FIG.47. In this embodiment, EFL=0.391 mm; HFOV=70.000 degrees; TTL=1.225 mm;Fno=2.200; ImgH=0.339 mm.

Ninth Embodiment

Please refer to FIG. 22 which illustrates the ninth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.23A for the longitudinal spherical aberration on the image plane 91 ofthe ninth embodiment; please refer to FIG. 23B for the field curvatureaberration on the sagittal direction; please refer to FIG. 23C for thefield curvature aberration on the tangential direction, and please referto FIG. 23D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the periphery region 14 of the object-side surface 11 of thefirst lens element 10 is convex, the periphery region 24 of theobject-side surface 21 of the second lens element 20 is concave, theoptical axis region 33 of the object-side surface 31 of the third lenselement 30 is convex and the periphery region 37 of the image-sidesurface 32 of the third lens element 30 is convex.

The optical data of the ninth embodiment of the optical imaging lens areshown in FIG. 48 while the aspheric surface data are shown in FIG. 49.In this embodiment, EFL=0.428 mm; HFOV=54.989 degrees; TTL=1.217 mm;Fno=2.000; ImgH=0.350 mm. In particular: 1. the longitudinal sphericalaberration of the optical imaging lens in this embodiment is better thanthat of the optical imaging lens in the first embodiment; 2. thedistortion aberration of the optical imaging lens in this embodiment isbetter than that of the optical imaging lens in the first embodiment.

Tenth Embodiment

Please refer to FIG. 24 which illustrates the tenth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.25A for the longitudinal spherical aberration on the image plane 91 ofthe tenth embodiment; please refer to FIG. 25B for the field curvatureaberration on the sagittal direction; please refer to FIG. 25C for thefield curvature aberration on the tangential direction, and please referto FIG. 25D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the optical axis region 33 of the object-side surface 31 ofthe third lens element 30 is convex.

The optical data of the tenth embodiment of the optical imaging lens areshown in FIG. 50 while the aspheric surface data are shown in FIG. 51.In this embodiment, EFL=0.384 mm; HFOV=70.083 degrees; TTL=1.283 mm;Fno=2.000; ImgH=0.364 mm. In particular: the longitudinal sphericalaberration of the optical imaging lens in this embodiment is better thanthat of the optical imaging lens in the first embodiment.

Eleventh Embodiment

Please refer to FIG. 26 which illustrates the eleventh embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.27A for the longitudinal spherical aberration on the image plane 91 ofthe eleventh embodiment; please refer to FIG. 27B for the fieldcurvature aberration on the sagittal direction; please refer to FIG. 27Cfor the field curvature aberration on the tangential direction, andplease refer to FIG. 27D for the distortion aberration. The componentsin this embodiment are similar to those in the first embodiment, but theoptical data such as the radius of curvature, the lens thickness, theaspheric surface or the back focal length in this embodiment aredifferent from the optical data in the first embodiment. In addition, inthis embodiment, the optical axis region 33 of the object-side surface31 of the third lens element 30 is convex.

The optical data of the eleventh embodiment of the optical imaging lensare shown in FIG. 52 while the aspheric surface data are shown in FIG.53. In this embodiment, EFL=0.454 mm; HFOV=70.035 degrees; TTL=1.343 mm;Fno=2.050; ImgH=0.429 mm. In particular: the longitudinal sphericalaberration of the optical imaging lens in this embodiment is better thanthat of the optical imaging lens in the first embodiment.

Twelfth Embodiment

Please refer to FIG. 28 which illustrates the twelfth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.29A for the longitudinal spherical aberration on the image plane 91 ofthe twelfth embodiment; please refer to FIG. 29B for the field curvatureaberration on the sagittal direction; please refer to FIG. 29C for thefield curvature aberration on the tangential direction, and please referto FIG. 29D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the radius of curvature, the lens thickness, the asphericsurface or the back focal length in this embodiment are different fromthe optical data in the first embodiment. In addition, in thisembodiment, the third lens element 30 has positive refracting power, theoptical axis region 33 and the periphery region 34 of the object-sidesurface 31 of the third lens element 30 are convex, the fourth lenselement 40 has negative refracting power and the optical axis region 46and the periphery region 47 of the image-side surface 42 of the fourthlens element 40 are concave.

The optical data of the twelfth embodiment of the optical imaging lensare shown in FIG. 54 while the aspheric surface data are shown in FIG.55. In this embodiment, EFL=0.415 mm; HFOV=54.926 degrees; TTL=1.032 mm;Fno=2.000; ImgH=0.343 mm. In particular: the distortion aberration ofthe optical imaging lens in this embodiment is better than that of theoptical imaging lens in the first embodiment.

Thirteenth Embodiment

Please refer to FIG. 30 which illustrates the thirteenth embodiment ofthe optical imaging lens 1 of the present invention. Please refer toFIG. 31A for the longitudinal spherical aberration on the image plane 91of the thirteenth embodiment; please refer to FIG. 31B for the fieldcurvature aberration on the sagittal direction; please refer to FIG. 31Cfor the field curvature aberration on the tangential direction, andplease refer to FIG. 31D for the distortion aberration. The componentsin this embodiment are similar to those in the first embodiment, but theoptical data such as the radius of curvature, the lens thickness, theaspheric surface or the back focal length in this embodiment aredifferent from the optical data in the first embodiment. In addition, inthis embodiment, the optical axis region 46 and the periphery region 47of the image-side surface 42 of the fourth lens element 40 are concave.

The optical data of the thirteenth embodiment of the optical imaginglens are shown in FIG. 56 while the aspheric surface data are shown inFIG. 57. In this embodiment, EFL=0.442 mm; HFOV=60.021 degrees;TTL=1.649 mm; Fno=2.448; ImgH=0.354 mm.

Some important parameter and ratios in each embodiment are shown in FIG.58 and in FIG. 59.

The embodiments of the present invention have the following advantageousefficacy:

1. When the optical axis region of the object-side surface of the secondlens element is convex, the optical axis region of the image-sidesurface of the third lens element is concave, Tavg≤350 μm, andGmax/Tmin≥1.000, the combination of the surface shapes and thethicknesses to go with the air gaps may effectively improve thedistortion and the aberration of the entire optical imaging lens so thatthe optical imaging lens of the present invention may have good opticalperformance. The further satisfaction of Tmax−T2≤λ may reduce the sizeof the optical imaging lens to reach the purpose of thinning. Notably,λ=0 when T2=Tmax, and λ=90 μm if T2≠Tmax. The preferable range of Tavgmay be 100 μm≤Tavg≤350 μm, and the preferable range of Gmax/Tmin may be1.000≤Gmax/Tmin≤7.400.

2. When the first lens element has negative refracting power and anoptical axis region of the object-side surface of the first lens elementis convex, the field of view of the optical imaging lens may beenlarged. The further limitations to go with that the optical axisregion of the image-side surface of the third lens element is concaveand Tavg≤400 μm may correct the aberration so that the optical imaginglens may have good optical performance. The further satisfaction ofTmax−T2≤λ and T3−Tmin≤δ may effectively reduce the size of the opticalimaging lens to satisfy the purpose of thinning. Notably, λ=0 whenT2=Tmax, λ=90 μm if T2≠Tmax, δ=0 when T3=Tmin, and δ=150 μm if T3=Tmin,and the preferable range of Tavg may be 100 μm≤Tavg≤400 μm.

3. When the optical axis region of the object-side surface of the firstlens element is convex, the optical axis region of the image-sidesurface of the third lens element is concave and |υ1−υ2|≤30.000, thecombinations of the surface shapes and the materials may make the fieldof view of the optical imaging lens to be enlarged, the local aberrationcorrected and the chromatic aberration improved. The further control ofTavg≤300 μm may effectively reduce the size of the optical imaging lensto reach the purpose of thinning. The preferable range of |υ1−υ2| may be0.000≤|υ1−υ2|≤30.000, and the preferable range of Tavg may be 100μm≤Tavg≤300 μm.

4. When the lens satisfies υ1+υ2≥93.000 and υ3+υ4≥70.000, it isbeneficial to the transmission and deflection of imaging rays and tofurther improve the chromatic aberration so that the optical imaginglens may have excellent imaging quality. The preferable range of υ1+υ2may be 93.000≤υ1+υ2≤120.000, and the preferable range of υ3+υ4 may be70.000≤υ3+υ4≤83.500.

5. To ensure the thinning of the optical imaging lens, it may havebetter optical performance when G12<ALT is met.

6. When Fno or HFOV satisfies the following proportional relationships,it is beneficial to reduce the f-number to increase the luminous flux ofthe optical imaging lens or to enlarge the field of view, so that thepresent invention may have better optical quality:

A) HFOV/(TTL+EFL)≥18.000 degrees/mm, and the preferable range is 18.000degrees/mm≤HFOV/(TTL+EFL)≤47.500 degrees/mm;B) HFOV/Fno≥18.500 degrees, and the preferable range is 18.500degrees≤HFOV/Fno≤38.500 degrees.

7. When the resolution and the system length of the optical imaging lensare taken into consideration, the present invention may compromisebetween the pixels and the resolution while the purpose of thinning maybe satisfied when TTL/ImgH≥3.000 to maintain the good imaging quality ofthe present invention. The preferable range is 3.000≤TTL/ImgH≤8.900.

8. In order to shorten the system length of the optical imaging lens andto ensure the imaging quality, the air gaps between lens elements orlens thicknesses may be adjusted appropriately or kept in suitableratios or EFL, BFL, the air gaps between lens elements or lens elementthicknesses may be suitably combined or designed, but the difficulty ofmanufacturing and the imaging quality must be taken into considerationat the same time. Therefore, if the numerical limits of the followingrelationships are satisfied, the embodiments of the present inventionmay have better configurations:

TTL/T2≤8.700, the preferable range is 4.200≤TTL/T2≤8.700;AAG/Tmin≤7.700, the preferable range is 1.200≤AAG/Tmin≤7.700;EFL/(G23+T3+G34)≥1.490, the preferable range is1.490≤EFL/(G23+T3+G34)≤8.600;(ALT+EFL)/(G12+T3+T4)≤3.200, the preferable range is1.200≤(ALT+EFL)/(G12+T3+T4)≤3.200;EFL/Gmax≤3.500, the preferable range is 0.700≤EFL/Gmax≤3.500;TL/(G12+T4)≤2.700, the preferable range is 1.700≤TL/(G12+T4)≤2.700;AAG/T1≤3.500, the preferable range is 0.850≤AAG/T1≤3.500;(EFL+BFL)/(T1+T4)≤3.700, the preferable range is1.400≤(EFL+BFL)/(T1+T4)≤3.700;BFL/(G12+G34)≤2.900, the preferable range is 0.850≤BFL/(G12+G34)≤2.900;TL/(G12+G34)≤5.100, the preferable range is 2.100≤TL/(G12+G34)≤5.100;ALT/(T1+G34)≤5.000, the preferable range is 1.900≤ALT/(T1+G34)≤5.000;BFL/(G23+T4)≥1.500, the preferable range is 1.500≤BFL/(G23+T4)≤3.900;(ALT+BFL)/(AAG+EFL)≥0.900, the preferable range is0.900≤(ALT+BFL)/(AAG+EFL)≤2.900;(TTL+EFL)/(Tmax+Tmax2)≤5.850, the preferable range is2.700≤(TTL+EFL)/(Tmax+Tmax2)≤5.850.

Any arbitrary combination of the parameters of the embodiments can beselected additionally to increase the lens limitation so as tofacilitate the design of the same structure of the present invention.

In the light of the unpredictability of the optical imaging lens, theabove conditional formulas preferably suggest the above principles tohave a shorter system length of the optical imaging lens, an enlargedfield of view, better imaging quality or a better fabrication yield toovercome the drawbacks of prior art. Some of the lens elements in theembodiments of the present invention may be made of a plastic materialto reduce the weight of the optical imaging lens and to reduce theproduction cost.

The contents in the embodiments of the invention include but are notlimited to a focal length, a thickness of a lens element, an Abbenumber, or other optical parameters. For example, in the embodiments ofthe invention, an optical parameter A and an optical parameter B aredisclosed, wherein the ranges of the optical parameters, comparativerelation between the optical parameters, and the range of a conditionalexpression covered by a plurality of embodiments are specificallyexplained as follows:

(1) The ranges of the optical parameters are, for example, α₂≤A≤α₁ orβ₂≤B≤β₁, where α₁ is a maximum value of the optical parameter A amongthe plurality of embodiments, α₂ is a minimum value of the opticalparameter A among the plurality of embodiments, β₁ is a maximum value ofthe optical parameter B among the plurality of embodiments, and β₂ is aminimum value of the optical parameter B among the plurality ofembodiments.(2) The comparative relation between the optical parameters is that A isgreater than B or A is less than B, for example.(3) The range of a conditional expression covered by a plurality ofembodiments is in detail a combination relation or proportional relationobtained by a possible operation of a plurality of optical parameters ineach same embodiment. The relation is defined as E, and E is, forexample, A+B or A−B or A/B or A*B or (A*B)^(1/2), and E satisfies aconditional expression E≤γ₁ or E≥γ₂ or γ₂≤E≤γ₁, where each of γ₁ and γ₂is a value obtained by an operation of the optical parameter A and theoptical parameter B in a same embodiment, γ₁ is a maximum value amongthe plurality of the embodiments, and γ₂ is a minimum value among theplurality of the embodiments.

The ranges of the aforementioned optical parameters, the aforementionedcomparative relations between the optical parameters, and a maximumvalue, a minimum value, and the numerical range between the maximumvalue and the minimum value of the aforementioned conditionalexpressions are all implementable and all belong to the scope disclosedby the invention. The aforementioned description is for exemplaryexplanation, but the invention is not limited thereto.

The embodiments of the invention are all implementable. In addition, acombination of partial features in a same embodiment can be selected,and the combination of partial features can achieve the unexpectedresult of the invention with respect to the prior art. The combinationof partial features includes but is not limited to the surface shape ofa lens element, a refracting power, a conditional expression or thelike, or a combination thereof. The description of the embodiments isfor explaining the specific embodiments of the principles of theinvention, but the invention is not limited thereto. Specifically, theembodiments and the drawings are for exemplifying, but the invention isnot limited thereto.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens, from an object side toan image side in order along an optical axis comprising: a first lenselement, a second lens element, a third lens element and a fourth lenselement, the first lens element to the fourth lens element each havingan object-side surface facing toward the object side and allowingimaging rays to pass through as well as an image-side surface facingtoward the image side and allowing the imaging rays to pass through, theoptical imaging lens comprising: an optical axis region of theobject-side surface of the second lens element is convex; an opticalaxis region of the image-side surface of the third lens element isconcave; and lens elements included by the optical imaging lens are onlythe four lens elements described above; wherein Tavg is an average offour thicknesses from the first lens element to the fourth lens elementalong the optical axis, Gmax is the largest value of three air gaps fromthe first lens element to the fourth lens element along the opticalaxis, Tmax is the largest thickness of four lens elements from the firstlens element to the fourth lens element along the optical axis, Tmin isthe smallest thickness of four lens elements from the first lens elementto the fourth lens element along the optical axis, and T2 is a thicknessof the second lens element along the optical axis to satisfy: Tavg≤350μm, Gmax/Tmin≥1.000, Tmax−T2≤λ; λ=0 when T2=Tmax, and λ=90 μm ifT2≈Tmax.
 2. The optical imaging lens of claim 1, wherein TTL is adistance from the object-side surface of the first lens element to animage plane along the optical axis, and the optical imaging lenssatisfies the relationship: TTL/T2≤8.700.
 3. The optical imaging lens ofclaim 1, wherein AAG is a sum of three air gaps from the first lenselement to the fourth lens element along the optical axis, and theoptical imaging lens satisfies the relationship: AAG/Tmin≤7.700.
 4. Theoptical imaging lens of claim 1, wherein EFL is an effective focallength of the optical imaging lens, T3 is a thickness of the third lenselement along the optical axis, G23 is an air gap between the secondlens element and the third lens element along the optical axis and G34is an air gap between the third lens element and the fourth lens elementalong the optical axis, and the optical imaging lens satisfies therelationship: EFL/(G23+T3+G34)≥1.490.
 5. The optical imaging lens ofclaim 1, wherein ALT is a sum of thicknesses of all the four lenselements along the optical axis, EFL is an effective focal length of theoptical imaging lens, T3 is a thickness of the third lens element alongthe optical axis, T4 is a thickness of the fourth lens element along theoptical axis and G12 is an air gap between the first lens element andthe second lens element along the optical axis, and the optical imaginglens satisfies the relationship: (ALT+EFL)/(G12+T3+T4)≤3.200.
 6. Theoptical imaging lens of claim 1, wherein EFL is an effective focallength of the optical imaging lens, and the optical imaging lenssatisfies the relationship: EFL/Gmax≤3.500.
 7. The optical imaging lensof claim 1, wherein HFOV is a half field of view of the optical imaginglens, TTL is a distance from the object-side surface of the first lenselement to an image plane along the optical axis and EFL is an effectivefocal length of the optical imaging lens, and the optical imaging lenssatisfies the relationship: HFOV/(TTL+EFL)≥18.000 degrees/mm.
 8. Anoptical imaging lens, from an object side to an image side in orderalong an optical axis comprising: a first lens element, a second lenselement, a third lens element and a fourth lens element, the first lenselement to the fourth lens element each having an object-side surfacefacing toward the object side and allowing imaging rays to pass throughas well as an image-side surface facing toward the image side andallowing the imaging rays to pass through, the optical imaging lenscomprising: the first lens element has negative refracting power and anoptical axis region of the object-side surface of the first lens elementis convex; an optical axis region of the image-side surface of the thirdlens element is concave; and lens elements included by the opticalimaging lens are only the four lens elements described above; whereinTavg is an average of four thicknesses from the first lens element tothe fourth lens element along the optical axis, Tmax is the largestthickness of four lens elements from the first lens element to thefourth lens element along the optical axis, Tmin is the smallestthickness of four lens elements from the first lens element to thefourth lens element along the optical axis, T2 is a thickness of thesecond lens element along the optical axis and T3 is a thickness of thethird lens element along the optical axis to satisfy: Tavg≤400 μm,Tmax−T2≤λ, T3−Tmin≤δ; λ=0 when T2=Tmax, λ=90 μm if T2 Tmax, δ=0 whenT3=Tmin, and δ=150 μm if T3≠Tmin.
 9. The optical imaging lens of claim8, wherein TL is a distance from the object-side surface of the firstlens element to the image-side surface of the fourth lens element alongthe optical axis, T4 is a thickness of the fourth lens element along theoptical axis and G12 is an air gap between the first lens element andthe second lens element along the optical axis, and the optical imaginglens satisfies the relationship: TL/(G12+T4)≤2.700.
 10. The opticalimaging lens of claim 8, wherein AAG is a sum of three air gaps from thefirst lens element to the fourth lens element along the optical axis andT1 is a thickness of the first lens element along the optical axis, andthe optical imaging lens satisfies the relationship: AAG/T1≤3.500. 11.The optical imaging lens of claim 8, wherein EFL is an effective focallength of the optical imaging lens, BFL is a distance from theimage-side surface of the fourth lens element to an image plane alongthe optical axis, T1 is a thickness of the first lens element along theoptical axis and T4 is a thickness of the fourth lens element along theoptical axis, and the optical imaging lens satisfies the relationship:(EFL+BFL)/(T1+T4)≤3.700.
 12. The optical imaging lens of claim 8,wherein υ3 is an Abbe number of the third lens element and υ4 is an Abbenumber of the fourth lens element, and the optical imaging lenssatisfies the relationship: υ3+υ4≥70.000.
 13. The optical imaging lensof claim 8, wherein BFL is a distance from the image-side surface of thefourth lens element to an image plane along the optical axis, G12 is anair gap between the first lens element and the second lens element alongthe optical axis and G34 is an air gap between the third lens elementand the fourth lens element along the optical axis, and the opticalimaging lens satisfies the relationship: BFL/(G12+G34)≤2.900.
 14. Theoptical imaging lens of claim 8, wherein HFOV is a half field of view ofthe optical imaging lens and Fno is a f-number of the optical imaginglens, and the optical imaging lens satisfies the relationship:HFOV/Fno≥18.500 degrees.
 15. An optical imaging lens, from an objectside to an image side in order along an optical axis comprising: a firstlens element, a second lens element, a third lens element and a fourthlens element, the first lens element to the fourth lens element eachhaving an object-side surface facing toward the object side and allowingimaging rays to pass through as well as an image-side surface facingtoward the image side and allowing the imaging rays to pass through, theoptical imaging lens comprising: an optical axis region of theobject-side surface of the first lens element is convex; an optical axisregion of the image-side surface of the third lens element is concave;and lens elements included by the optical imaging lens are only the fourlens elements described above; wherein Tavg is an average of fourthicknesses from the first lens element to the fourth lens element alongthe optical axis, an Abbe number of the first lens element is υ1, and anAbbe number of the second lens element is υ2 to satisfy: Tavg≤300 μm,and |υ1−υ2|≤30.000.
 16. The optical imaging lens of claim 15, wherein TLis a distance from the object-side surface of the first lens element tothe image-side surface of the fourth lens element along the opticalaxis, G12 is an air gap between the first lens element and the secondlens element along the optical axis and G34 is an air gap between thethird lens element and the fourth lens element along the optical axisand the optical imaging lens satisfies the relationship:TL/(G12+G34)≤5.100.
 17. The optical imaging lens of claim 15, whereinALT is a sum of thicknesses of all the four lens elements along theoptical axis, T1 is a thickness of the first lens element along theoptical axis and G34 is an air gap between the third lens element andthe fourth lens element along the optical axis and the optical imaginglens satisfies the relationship: ALT/(T1+G34)≤5.000.
 18. The opticalimaging lens of claim 15, wherein BFL is a distance from the image-sidesurface of the fourth lens element to an image plane along the opticalaxis, T4 is a thickness of the fourth lens element along the opticalaxis and G23 is an air gap between the second lens element and the thirdlens element along the optical axis, and the optical imaging lenssatisfies the relationship: BFL/(G23+T4)≥1.500.
 19. The optical imaginglens of claim 15, wherein TTL is a distance from the object-side surfaceof the first lens element to an image plane along the optical axis andImgH is an image height of the optical imaging lens, and the opticalimaging lens satisfies the relationship: TTL/ImgH≥3.000.
 20. The opticalimaging lens of claim 15, wherein ALT is a sum of thicknesses of all thefour lens elements along the optical axis, BFL is a distance from theimage-side surface of the fourth lens element to an image plane alongthe optical axis, AAG is a sum of three air gaps from the first lenselement to the fourth lens element along the optical axis and EFL is aneffective focal length of the optical imaging lens, and the opticalimaging lens satisfies the relationship: (ALT+BFL)/(AAG+EFL)≥0.900.